Hereditary Hemolytic Anemias — Membrane Defects

A 28-year-old Indian woman presents to the outpatient clinic with a 3-year history of intermittent jaundice, dark urine, and fatigue. She reports that symptoms worsen during infections and after eating fava beans. On examination, she is icteric with mild splenomegaly. Laboratory investigations reveal: Hemoglobin 9.2 g/dL, reticulocyte count 8%, indirect bilirubin 3.2 mg/dL, haptoglobin <10 mg/dL, and LDH 680 U/L. Peripheral blood smear shows bite cells and Heinz bodies. Osmotic fragility test is normal. What is the most likely diagnosis?

A 5-year-old boy of Bengali descent is brought to the pediatric clinic with a 2-year history of recurrent jaundice, dark urine, and pallor. His maternal uncle had similar symptoms and underwent splenectomy. On examination, he is icteric with moderate splenomegaly and mild hepatomegaly. Laboratory findings: Hemoglobin 8.5 g/dL, reticulocyte count 12%, indirect bilirubin 4.1 mg/dL, haptoglobin 15 mg/dL, LDH 920 U/L. Osmotic fragility test shows increased fragility of RBCs. Peripheral blood smear reveals spherocytes. The child's symptoms worsen during infections but not with fava bean ingestion. What is the most likely diagnosis?

Which of the following laboratory findings is characteristic of hereditary elliptocytosis?

In hereditary spherocytosis, which membrane protein defect is most commonly responsible for the disease?